Screw propeller



Aug. 9, 1927. y 1,638,695

H. LEITNER SCREW PROPELLER Filed June 8. 1925 2 Sheets-Sheet l Aug. 9, 1927a H. LEITNER SCREW PROPELLER F 1` d June 8. 1925 h h l 2 Sheets-Sheet 2 .J 10%.@ km

Patented Aug. 9, 1927.

HENRY LEI'INER, OF CROYDON', ENG.

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Application filed .Tune 8, 1925, Serial No. 35,676, and in Great Britain .Tune 28, 192th This inventionI relates to screw-propellers, primarily intended for use on aircraft, and wherein the 'blades are detachable and adjustable for pitch.

The object of this invention is to provide a propeller blade in which various disadvantages usually exist-ing in blades of this type of ropeller are eliminated.

According to the invention I form each of the blades of a propeller of a single or composite plate the two faces of which are shaped to provide .the acting or working faces ofthe blade, the thick or root end of the shaped plate being thickened to form 16 the root of the blade by pieces applied and secured to the two faces thereof.

In a suitable arrangement for carrying out the inventiona plate, or -a number of plates joined together to form a composite 20 plate, or metal vor non-metallic' materlal'ls shaped to provide the acting or vWorking faces of the blade, this shaping, preferably,

, stopping a short distance from the root end of the plate. The edges of the unshaped portion of the plate are then reduced or cut away so as to present a shape in outline like the neck of a bottle. On each of. the iiat faces of this portion is formed an annular, straight or other shaped projection or groove or recess, or a series thereof.

Two pieces of material similar to that of the blade, or of other suitable material, are shaped'so that when contiguous they form a body of ogival form and resemble in shape a h'i'gh explosive shell or a bullet, and on their opposed atifaces are formed grooves or pro ections to correspond with those on the en of the shaped plate.

These two pieces are then placed on opposite sides of the reduced portion'of t e blade and clamped thereto by rivets, screwsy or the like and form the root of the blade; or they can be joined Athereto by Welding, brazing or the like.

A' finishing cut is then taken from the said root to provide a journal or such ledges or grooves as are necessary for fixation to the ro eller vhub by engagement in a socket on t e atter, twov or more. of such blades, similarly arranged, forming a complete propeller. l To enable the invention to be fully understood I will describe it by reference to the accompanying drawing, in which Figures 1 and 2 are, respectively, elevations at right-angles of the root or butt end and a portion of the acting part of a propeller blade constructed in accordance with th invention.

Figures 3, 4 and 5 are, respectively, sections on the lines 3-3, 4 4 and 55, Figure l. i

Figure 6 is a view similar t`o Figure 1,

illustrating a modification and Figure 7 is a sectional elevation at rightangles to Figure 6.

Figures 8 and 9 are sections on the lines 8 8, and 99, Figure 6.

a is the simple or composite plate or block of'metal or non-metallic material which is shaped, to provide the working or acting faces o'f a propeller blade. y

The shaping of the blade is not extendedl to the` termination of the root end of the plate a so that the latter is left at this part, indicated at g1, iat on either face and is then sha ed at the edges to the outline of a bottle nec as shown, and formed, in the construction illustrated in Figures 1 to 5, with a series of projections h, the spacesbet-ween which constitute grooves z'. j, j are the two pieces of material, which may be the same as that of the blade, which are applied to the opposite faces of the flat part b to form 'therewith the root of the blade and which pieces, if contiguous, form a body of-ogival form. k, la are the projections formed on of the piece a and Z, Z are the rivets by which the said pieces y', y' are secured to the art gl the said pieces j, j to fit into vthe grooves i of the blade. Or, in place of the rlvets Z,

screws or the like may be employed.. Or, instead of the rivets, screws, etc., I may, where the artsare-of metal, weld or braze them toget er.

In the construction illustrated in Figures l to 5, the grooves z' and projections k are formed straight and parallel, whereas in the construction illustrated in Figures 6 to 9 the said grooves and projections are of annular form.

fm, indicates a groove cut in the root of the blade to form a journal to fit into a socket in the hub so that the blade can vbe adjusted therein to vary its pitch. Or, the root may be lodged, grooved or formed in any other manner for the same purpose.

Claims- 1. In a screw propeller of the character described, .a blade body, and means applied los to opposite faces of said body at the root end forming a cylindrical root, recessed circumferentially.

2. In a screw propeller of the character described, a blade body having the longi- V tudinal edges at the root end thereof cut inwardly to provide a relatively narrow root portion, and a pair of elono'ated bodies secured one onv either face ofD said root portion forming at their outer extremities, with the root portion, a cylindrical root body for engagement in a hub, substantially as and for the purpose described. l

A 3. In a screw propeller of the character described, a blade body having the longitudinal edges at the root end thereof cut` described, a-blade body having the longitudinal edges at the root end thereof cut inwardly to provide a relatively narrow root ortion, and a air ofbodies of lsubstantialy ogival con guration and substantially semi-circularl cross sectional design secured one against each face of said narrow root portion, the outer extremities of said bodies forming, with the adjacent blade portion, :a cylindrical root designed to be mounted in a hub to permit axial rotation of the blade.

5. In a screw propeller of the character described, a blade body having a relatively narrow flat root portion, an outwardly projecting rib formed on each face of said root portion, and a pair of elongated members extending longitudinally of the blade one against each face of said root portion, each body having the blade contacting face thereof formed'to receive the adjacent rib and. said bodies further having the outer extremities thereof desi ned toform, with the root portion, a cylin rical blade root, substantially as and forthe purpose described.

6. In a screw propeller of the character described,a blade body having a relatively narrow fiat vroot portion, an outwardly projecting rib formed on each face of said rootortion and a pair of bodies of ogival conguration and substantially semi-circular cross sectional l'design secured one against each face ofgthe root portion, each body having the blade contacting face formed to receive the adjacent rib and said bodies further having the youter extremities thereof designed to form, with the root portion, a cylindrical blade root, substantially as and .for the purpose set forth.

7. In a screw propeller of the character described, a blade body having a relatively narrow fiat root portion, a plurality of rib members 'formed transversely of each face of said fiat root portion, and a air of bodies of elongated ogival configuration and substantiall semi-circular cross sectional design secure one against each face of the root portion, each bod having the blade contacting face provide with a plurality of transverse grooves to receive the adjacent ribs and' said bodies further having the outer extremities thereof designed to form with the root portion, a clindrical blade root. ENRY LEITNER. 

